PREGNANCY OF UNKOWN LOCATION(PUL)

Dr. Omneya Nagy Elmakhzangy

Special Fetal Care unit

Ain Shams Univeristy

What is PUL?

The term PUL is used whenever there is no sign of either intra or extrauterine pregnancy or retained products of conception on transvaginal ultrasound.

Up to 31% of women attending early pregnancy assessment centres have a PUL though the experience of the sonographer can reduce this to 10%.

Positive Urine Pregnancy Test

Transvaginal ultrasound scan

PUL / Inconclusive scan

Haemodynamically stable Pain free

Haemodynamically stable in pain

Haemodynamically unstable in pain

Expectant management Admit and Serum hCG

Consider laparotomy

>66% increase in SerumhCG 0‐48 hours

<66% increase or <15%decrease in Serum hCG 0‐48 hrs

>15% decrease in SerumhCG 0‐48 hrs

? Intra Uterine Pregnancy ? Ectopic pregnancy

? Failing PUL

Serum hCG in 48 hrs.Rescan if hCG >1000 IU/L

Repeat serum hCG in 1week to confirm failing pregnancy

Early IUPEctopic

pregnancyPUL

Rescan 2 weeks toconfirm viability

Management asclinically indicated

Repeat hCG nowand 48 hrs later

Consider weekly hCG monitoring until < 25IU/L

If no pregnancy seen on repeat scan and suboptimal rise in hCG, consider methotrexate

Serum hCG at 0 & 48 hrs

Rescan in 1 week toconfirm pregnancy location

Consider laparoscopy or medical management

Discriminatory zone of hCG The discriminatory zone of β-HCG is the

level above which an imaging scan should reliably visualize a gestational sac within the uterus in a normal intrauterine pregnancy is as follows:

1- 1500-1800 mIU/mL with transvaginal ultrasonography, but up to 2300 mIU/mL with multiple gestations .

2- 6000-6500 mIU/mL with abdominal ultrasonography.

Serum progesterone levels Progesterone level < 25 nmol/l,

associated with nonviable pregnancy (viable in 0.3%).

Progesterone < 20 nmol/l predicts failing pregnancy.

Levels > 25 nmol/l are associated with pregnancies.

Levels > 60 nmol/l are strongly associated with intrauterine pregnancy (2.6% ectopic).

Scanning Modalities

Gestational sac TAUS

Gestational sac TVUS

3 D Scanning

3D of interstitial Pregancy

Doppler & 3D

MRI in Ectopic pregnancy

Abdominal pregnancy

Endometrial Findings Suggestive of intrauterine Pregnancy

 Double decidual sac sign (DDSS)  Is a useful feature on early pregnancy ultrasound

in distinguishing between an early intrauterine pregnancy (IUP) and a pseudogestational sac. It consists of the decidua parietalis (that lining the uterine cavity) and decidua capsularis (lining the gestational sac).

Gestational Sac and pseudogestational sac

Decidual Cyst

Decidual cysts appearing at the junction of endometrium and myometrium are associated with both intrauterine and ectopic pregnancy.

Endometrial FINDINGS DIAGNOSTIC OF INTRAUTERINE PREGNANCY

Diamond ring appearance of FP and YS

Adenexal Findings

Ovaries Fallopian tubes

Corpus luteum

Tubal Ectopic pregnancy

Adenxal mass

Adenxal ectopic pregnancy with positive cardiac pulsation

Rare Ectopic Sites

Interstitial pregnancy

Ovarian Ectopic

Cervical Ectopic

Heterotropic Pregnancy

Peritoneal Free Fluid

Ring of fire Sign The ring of fire sign also known as ring of

vascularity signifies a hypervascular lesion with peripheral vascularity on colour or pulsed Doppler examination of pelvis due to low impedance high diastolic flow .

This sign can be seen in highly vascular pelvic lesions like:

1-corpus luteum cyst (more commonly)

2-ectopic pregnancy

Failed Early Pregnancy

failed early pregnancypregnancy of uncertain viability (PUV)

Abortionthreatened abortionmissed abortioninevitable abortionIncomplete abortioncomplete abortion

Missed Abortion Major criteria A pregnancy is considered non-viable on transvaginal ultrasound if: no fetal heart beat where:

CRL ≥ 7 mm no fetal pole where:

G.S > 25 mm with no embryo If a fetal pole is present, fetal pole measurements override MSD

measurement.  Both fetus and gestational sac are expected to grow 1mm/day. Hence,

absence or inadequate growth on serial scans at least 7-10 days apart is suggestive of non-viability.

Other poor prognostic indicators include: no yolk sac, where:

G.S > 8 mm embryo seen

irregular gestational sac low position of the gestational sac

Pregnancy of uncertain viability Pregnancy of uncertain viability (PUV) is a term given to an

intrauterine pregnancy in a situation where there are not enough criteria (usually on ultrasound grounds) to confidently categorise a pregnancy as a miscarriage.  

On transvaginal ultrasound: an empty intrauterine gestational sac measuring less than 20mm

in mean sac diameter 1.  an intrauterine gestational sac containing a fetal pole with a 

crown-rump length(CRL) of less than 6mm with no fetal cardiac activity .

gestational sac < 25mm in mean diameter and containing yolk sac only .

In these situations a follow up ultrasound scan in 7-14 days with serial beta HCG correlation is recommended as some of these pregnancies may progress to be a viable pregnancy. 

Inevitable abortion An inevitable abortion refers to the

presence of an open internal os in the presence of bleeding in the first trimester of pregnancy.  Most often intra cervical contents are present at the time of examination.

Incomplete abortion with retained Products of conception

Complete Abortion